Hastelloy C-22 (UNS N06022)
The higher-chromium C alloy — better than C-276 in oxidising acids, ferric and cupric chlorides and wet chlorine, with the same resistance to pitting and stress-corrosion cracking.
What Hastelloy C-22 is.
Hastelloy C-22 raises chromium to 22 percent and trims molybdenum to 13 percent compared with C-276. The extra chromium improves resistance to oxidising environments such as nitric acid, ferric and cupric chlorides and wet chlorine, while molybdenum and tungsten keep the alloy's resistance to reducing acids and to chloride pitting and crevice corrosion.
ASTM B574 covers the rod. We machine C-22 studs, bolts, nuts and components from certified B574 rod for chemical, pharmaceutical and pollution-control service.
Chemical composition.
| Element | Symbol | Min % | Max % |
|---|---|---|---|
| Nickel | Ni | balance | — |
| Chromium | Cr | 20.0 | 22.5 |
| Molybdenum | Mo | 12.5 | 14.5 |
| Iron | Fe | 2.0 | 6.0 |
| Tungsten | W | 2.5 | 3.5 |
| Cobalt | Co | — | 2.5 |
| Manganese | Mn | — | 0.50 |
| Vanadium | V | — | 0.35 |
| Carbon | C | — | 0.015 |
| Silicon | Si | — | 0.08 |
| Phosphorus | P | — | 0.02 |
| Sulfur | S | — | 0.02 |
Values per ASTM B574-18 Table 1 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team.
Mechanical properties.
| Condition and size | Tensile strength, min (ksi) | Yield strength 0.2%, min (ksi) | Elongation, min (%) |
|---|---|---|---|
| Solution annealed — all sizes | 100 | 45 | 45 |
Values per ASTM B574-18 Table 5 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team.
Specifications that apply.
How Hastelloy C-22 ships from Houston.
- Full-thread studs and stud bolts
- Hex and heavy hex bolts
- Socket head cap screws
- Hex nuts in the same alloy
- Threaded rod
- Machined components from certified bar
Hastelloy C-22 fasteners we make.
Every item is manufactured to your drawing or standard in Hastelloy C-22, imperial or metric, with an EN 10204 3.1 certificate.
C-22 or C-276?
Both are low-carbon nickel-chromium-molybdenum-tungsten alloys with the same 100 ksi annealed strength and excellent weldability. C-276 has more molybdenum and is the choice for strongly reducing acids and the highest resistance to localised chloride attack; C-22 has more chromium and is the choice where the stream is oxidising, contains ferric or cupric ions, or swings between oxidising and reducing conditions. Many users standardise on C-22 as the more versatile alloy for mixed and unknown services.
Testing, certification and marking
- Tensile and hardness tested per lot on the finished product
- Grade or alloy marking C-22 with heat number and manufacturer's identification on every piece
- EN 10204 3.1 material test report with heat number and chemistry; 3.2 witness available
Hastelloy C-276 (UNS N10276)
The universal chemical-process alloy — resists oxidising and reducing acids, wet chlorine and sour gas — and the F468 fastener grade Ni 276.
ASTM B335 rod · F468 / F467 list the related N10001 alloyHastelloy B-2 (UNS N10665)
The hydrochloric-acid alloy — 28 % molybdenum for all concentrations of HCl and other reducing acids — and the F468 fastener grade Ni 335.
ASTM B446 bar · ASTM F468 / F467 fastenersInconel 625 (UNS N06625)
The corrosion all-rounder — 120 ksi in the annealed condition, resistant to seawater, sour gas, acids and oxidation to 1800 °F, and the F468 nickel fastener grade Ni 625.